Thermostatic control switch



June 13, 1950 GRADEN 2,511,256

THERMOSTATIC CONTROL swucn Filed sept. 25, 1947 2 Sheets-Sheet 1 IL TJr- E /7 INVENTOR.

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THERMOSTATIC CONTROL SWITCH Filed Sept. 25, 1947 2 Sheets-Sheet Z IF: E-fii IN V EN TOR.

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Patented June 13, 1950 THERMOSTATIC CONTROL SWITCH Russell Andrew Graden, Millville, Pa., assignor of two-thirds to Ralph Charies Graden, Harrisburg, Pa.

Application September 25, 1947, Serial No.'77'6,136

\ .8 Claims. 1

My invention relates .broadly to thermostats and'more particularly to an improved simplified constructionof thermostat having a high degree of'sensitivity for :the control of-1electrical circuits under conditions of changes in temperature.

Oneof theobjects of-my invention is to provide an improved construction 'of mercury switch thermostat including a'highly sensitive thermostatic element zopera'tive under conditions of changes inttemperature for actuating the mercury .switehiat anyadjusted setting ofthe device.

.A'rurther object of myrinvention is to provide "an :improved construction of mercury switch thermostat having a minimum number of parts associated with a thermostatic element adapted torangularlyflexpin its position under conditions of changes in temperature, for actuating the thermostatic: switch.

'A'still further object of my inventionis to prowide an :improved construction of adjustment uneans for. aimercury switch thermostat by which aithermostatic element may be adjusted in effective position to actuate at a predetermined temperature for 'imparting movement to a mercury switchmember for opening or closing an electricalicircuit.atthe adjusted temperature.

Other and further objects of my invention 'residein the simplified construction of mercury switch adjustable thermostat as set forth more :fully in therspecifi-cation hereinafter following by :reference to the accompanying drawings in which:

Figure 1 :is a front elevational view of the mercury switch thermostat constructed in accordance with i'myzinvention with the mercury or circuit closing position;

"Figure 7 isadetail front 'elevational'view oi. the :rotor member which supports the mercury contactorrand' serves to complete the electrical connections thereto;

Figure :8 is' aside'elevational "view of the rotor illustrated in Figure 7;

Figure 9 is -.a vertical sectional view taken substantially on line 9-9 of Figure '7;

Figure 10 is a horizontal sectional'viewtaken substantially on'1inel0-l0-,0f Figure'l; and

Figure 11 shows'a'modified arrangement of the rotor for supporting'two mercury switchdevices for control by'the thermostat.

My inventionis directed to an improved construction of mercurysWitchthermostat-of high sensitivity. The thermostat :is adjustable over a relatively widetemperature range for actuating the mercury switch at a predetermined adjusted temperature. Iprovide an arrangement-of rotor which carries one or more mercury-switch elements and in which flexibleleads from-the mercury switch connect to commutator elements electrically connected through the supporting frame to the circuit to-be'controlled.

The thermostat element is mounted on an angularly shiftable .lever member which is, in turn, pivotally coupled with an angularly shiftable indicator arm which is adjustable over a graduated scale calibrated to enable'the-adjustable arm to be setcat that temperature at which the mercury switch istobe actuated. The structure of my invention-has been foundtobehighly accurate and precise in its operation despite'the simplicity of its designand production.

Referring to the-drawings'in more-detail, reference character I designates a base of insulation material for supporting the parts of the thermostat, the base carrying adjacent-the. upper end thereof a scale member 2 having vgraduations 3 thereon calibratedin degrees over the temperature range over which the thermostatoperates. The graduationsare radiallyinclined toward a center indicated-at 4 which'is the pivotalpoint for the adjustable arm 5. At theeenter 4, which is an aperture insupport |,-I provide a centering bolt'member 6 havingaheaded end which serves to'confine-theadjustablearm 5 in pivotal position. A suitable spacer-member 1 .is disposed between the adjustable arm 5 and the support I so that the adjustable arm5 isfreeito beangularly shifted to any desired position over the scale The adjustable arm 5 isformed at the end Ea thereof into'a radiallyextending knife edge forming-with the pointer 52) an end portion for the adjustable arm which may be precisely aligned with a selected graduation on the scale 2 in setting the thermostat for operation at a predetermined temperature. 7

The opposite end of the adjustable arm 5, beyond the pivoted position provided by 'bolt member '5, is bifurcated, asrepresented at 50, to embrace the circular rheaded member :8 carried by the pivotally-mounted lever member-9 which is pivoted on member I9 adjacent the end of support I. The upper end of lever 9 extends beneath the bifurcated end of the adjustable arm 5, thus leaving the adjustable arm free to swing over the end of lever 9 with minimum friction. By setting the adjustable arm 5 at a particular angular position, indicated by the graduations 3 on the scale 2, lever 9 may be angularly positioned in a selected position on either side of the longitudinal center through the support I.

The lever 9 carries an insulating support I I adjacent the pivotally mounted end thereof and offset at one side thereof so that one plane surface of the insulating support II is substantially aligned with the longitudinal center of lever member 9. This location of the insulating support I I enables the thermostatic bi-metallic temperature-sensitive strip I2 to be supported at the lower end thereof precisely along the longitudinal center line of the lever member 9. The bi-metallic temperature-sensitive strip I2 is secured to the insulating support I! by means of securing screws I4 which maintain the bi-metallic temperature-sensitive strip I2 in a position extending in a substantially vertical direction with the opposite sides thereof exposed to the circulation of air or gases to which the bi-metallic temperature-sensitive strip I2 responds. The upper end of the strip I2 is cut away, as represented at I2a, and terminates in an upwardly directed tongue I2?) which serves to support the pin member I5 which is directed inwardly toward the support I. The mercury switch contactor, which is controlled by the bi-metallic strip I2, is mounted in a unique manner with respect to support I. I

Referring more particularly to Figure 5, it will be seen that two transversely extending plate members I6 and I I are mounted in spaced position with respect to support I by means of screw members I8 and IS; The screw members I8 and I9 are thoroughly insulated from the transversely extending plate members I6 and H by an arrangement of sleeve-like bushings of insulation material, which I have represented at 20 and 2|, projecting into the recesses in the support members 22 and 23 located between the transversely extending plate members IB and IT, as shown.

I provide metallic sleeve members 24 and 25 extending from the support I and projecting through spacer members of insulation material, shown at 2B and 21, and projectingthrough apertures in the transversely extending plate member I6 and into aligning recesses formed ininsulated spacer members 22 and 23, as represented at 22a and 23a. Nut members Isa and I9a serve to secure the screw members #8 and I9 in position for clamping transversely extending plate members I6 and I! in spaced position and in insulated relation one to the other. It will be observed that between insulated bushing 22 and transversely extending plate member I6 there is clamped the end of the terminal lug represented at 29, while between the transversely extending plate member I! and the end of the insulated bushing 23 there is clamped the end of the lug 29 and, thus, electrical connection may be established to both the transversely extending plate member I6 and the transversely extending plate member I'I. These transversely extending plate members I5 and I1 serve as terminals for opposite sides of the rotor member indicated generally at 39.

The rotor 39 is of laminated construction and is formed by a pair of electrical conductive circular plates SI and 32 each of which has stub shafts 33 and 34 secured therein and projecting axially 4 in opposite directions therefrom with their ends electrically insulated from each other by the central plate of insulation material represented at 35. The centra1 plate of insulation material is perforated at 35a and 35b for the passage of a coupling pin 36 extending from plate 3| and coupling pin 37 extending from the plate 32. The coupling pins 36 and 3! terminate short of the thickness of the central plate of insulation material 35 and, thus, while serving as driving means,

do not cause a short circuit between plate members 3| and 32. Thus, plate members 3! and 32 constitute opposite sides of the electrical circuit leading from the mercury switch represented by mercury tube 39 supported in the substantially cylindrical carrier 49 which is coextensive with the bracket portion 40a thereof and which is secured to the end of stub shaft 34. The mercury tube 39 includes a pair of electrical terminals 39a therein, adapted to be electrically bridged by the globule of mercury 3% when the mercury tube is angularly shifted to a position in which the globule of mercury 39b gravitates to the end of mercury tube containing the terminals 39a, as represented in the position of the device shown in Figure 6. Flexible leads 4| and 42 extend from the terminals 39c and enter sockets 32a, and 3Ia in plate members 32 and 3| of the rotor 39 extending through diametrically disposed apertures in the stub shafts 34 and 33. Thus, direct electrical connection is made through the 1eads extending from terminals 39a, of the mercury switch 39 to the rotor plates 32 and 3| and thence to stub shafts 34 and 33 without employment of sliding contact brushes. Good electrical connection is made between stub shafts 33 and 34 and transversely extending plate members I5 and I! by precision mounting of the stub shafts 33 and 34 in bearings Isa and IIa formed in the transversely extending plate members I6 and I1. These bearings have relatively wide surface contact with the stub shafts and, in addition, each stub shaft is provided with a frusto-conical shaped annular zone indicated at 33a. and 34a which bear directly against the inner faces of the plates I6 and I1, forming a continuous and good electrical connection therewith. This arrangement permits the lugs 28 and 29, which connect respectively with the plates I6 and IT, to establish goo d electrical connection through conductors 43 and 44 which pass through apertures 43a and 44a, in support I for connection to the device to be controlled.

In lieu of the single mercury switch 39 depicted in Figures 1 to 6, I may provide a multiplicity of mercury switch devices for simultaneous control by the thermostatic device. I have shown in Figure 11 the manner in which a special bracket 45 may be attached to the stub shaft 34 and support at opposite ends thereof the mercury switch tubes 49 and 41. The terminal ends of the mercury switch tubes 46 and 41 are located in diametrically opposite positions so that angular movement of rotor 39 will shift the mercury tubes 46 and 41 to an angular position in which the globules of mercury therein gravitate simultaneously to positions for bridging the circuit terminals in one position or gravitate away from the circuit terminals for opening the said circuits in the opposite position. The multiple control of electrical circuits through a multiplicity of independent mercury contactors operated simultaneously has many important applications.

The manner of actuating the rotor 30 by flexing of the bi-metallic strip I2 will be more fully ;nection with slot 311) of platei3l. :eircuit occurs bet-ween-plates 32-.an1d 3|,but .an angular displacement of rotor 3l-may be effected aunder control of theyflexing of bi-metallic member l2 suilicientto move bracket vd'fla of carrier Ml-to a positionrfor shifting the mercury tube '39 =.to "a position in ;which-. globu1e 3911 makes con- .nection with terminals 39a within the mercury .tube. ;mercury tubes are employed such as the two tubes represented in Figure 11.

rotor .30. ,asbi-metallic member [2 is'restored to its orig- =understood byreference :to :Figures .44, 7 and ;9, -from which it will :be observed that :the conductive :plate members .31 and 32 and :the central plate member -2-5 --are 1 all provided with a series of :radially disposedslots 321), :35!) and i-3Ib, :a'll aligned with each other. .carried'by the endof bi-metallic strip 12, enters slots 32b and partially enters 1 slot 35b, but does The pin member I 5,

not extend a suflicient distance to establish'con- :Thus, no short The operation is similar when additional The ,fact that the transversely extend'mg-con- -ductive plate members Ail-and 11 are spaced was .an assemblybyspacer'membersZ'S and .21 away from-support enables-the adiustablearm '5 to the freely shifted to the desiredangularposition vin the-space 4-8, as represented moreclearlyin .Figures 3 and5.

In lieu of the mounting ofthe lever-member :9

.andthe adjustable arm ,5 on the front "of the ssupport-l,.it is practicable inmany instances to 'mount the lever Brand the adjustable arm 25in theirear of-thesupportl pivotingthe lever ga to support I by member'lt, asheretofore explained, and pivoting the adjustable arm 5 to :support ;I bymember 6,'as heretoiore explainedpto allow the adjustable end of the adjustable arm 25 to project through a slot formedinsupport I 'for movement over the graduatedscale 3, as explained hereinbeiore.

The structure of my invention has-been found to be highly sensitive'in operation. Flerzingofv the bi-metallicmember l2 by movementof pin lafor angularly shifting the rotor 36 is effected by changes in temperature to which the bi- The structure l lends itself particularly to a reversal of themtire process-so that, instead of closing an electric circuit under conditions of rise in temperature,

metallic member I2 is exposed.

the electric circuit maybe opened upon such rise by reversing the position of the bracket 53a, the

carrier 40 and the mercury tube associated therewith. Thus,'the device may be used under conditionsof either increase or decrease in tempera- .ture in a reverse manner. Angularly positioning the lever member 9 is determinative of the position of the bi-metallic member 12 .and thereby .fixesthe metallic relation of the end of the bimetallic memberlZ and the rotor 3i). fIhebi- 'metallic member 12, in expanding and contracting, imparts proportional angular movement of The process is a continuous one, and,

inal position, corresponding restoration of the mercury switch is effected.

While I have found the structure of my invention, as explained herein, highly desirable in manufacture, production and operation, I realize that modifications in details of construction-may be made, and I desire it to be understood that no limitations upon myinvention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows: 1. A thermostatic electric circuit controller insulation materialatone end and .to said rotor at the :other end for imparting angular movement to. saidrmercury switch under conditions of :variable :temperature 3 and electrical connections :extending'from said switch through saidirotorito said .electrically conductive'plate members, whereby .said'plate members serve as terminals'for saidaswitch.

1 2. A thermostatic, electric circuit controller comprising abase. of insulation material, a frame structure; insulatingly supported with respect-to .saidrbase, said frame structure comprising a pair of electrically conductiveplate members, spacer members disposed between opposite ends of said plate members, a rotor journaled intermediate :said plate members,.acapsule enclosed mercury :switch device carried by said rotor and operative inzone angular position to close an elec- -trical1circuit andin another position to open the electrical circuit, a lever member pivotally mounted at oneend thereof onsaid base, a member. of insulation materialv carried by said lever member,athermo-sensitive element supported at none endon said member of said insulation material and'connected at the other end with said .rotorifor imparting angular movement to said :mercuryfiswitch under conditions of variable temperature, meansifor-angularly adjusting the posiation of said lever member, and. electrical connections extending from .said switch through said "rotor-to.- said electrically conductive plate members whereby said plate-members :serve as ter- --minalsfor said switch.

3. A :thermostatic electric circuit controller comprising a base of insulation material, a'frame ---structure :insulat-ingly: supported with respect to saidsbasa-said frame-structure comprising a'pair of electrically conductive plate members; spacer :members disposed between opposite ends of said plate members, a'rotor journale'd intermediate said plate members, a capsule enclosed mercury switchdevice carried by said. rotor and operative 'in-onezangularposition to. close an electrical cirlcuitsand'in another:position to open-the electrical circuit, .a lever member pivotallyi mounted at one end :on said e'base, anadjustable arm pivotally "mounted on :said base andxestablishing pivotal econnectionx-with the other end of said lever memher, aa standard of i insulation-material carried by said lever member, thermoesensitiveelemerit connected With said standard at one end and connected-with said rotor at the other end'for imparting angular movementto said mercury switch under-conditions of variable temperature, and electrical connections extending from said switch through said-rotor to said electrically'conductive platemembers whereby said plate members constitute zterminals for-said switch.

4. A thermostatic electric circuit controller comprising a base of insulation material, a frame structure insulatingly supported with respect to 'said base, said frame structure comprising a pair of electrically conductive plate members, spacer members disposed between opposite ends of said plate members, a rotor journaled intermediate said'plate members, a capsule enclosed mercury switch device carried by said rotor and operative in one angular position to close an electrical circuit and in another position to open the electrical circuit, a lever member pivotally mounted at one end on said base, an adjustable arm pivotally mounted intermediate its ends on said base and pivotally connected at one end to said lever member and terminating in an indicator pointer at the other end a calibrated scale carried by said base adjacent the last mentioned end of said adjustable arm for indicating in coaction with said indicator pointer a temperature setting at which a selected position of said adjustable arm over said calibrated scale operates to angularly displace said lever member, a standard of insulation material carried by said lever member, a thermo-sensitive element secured at one end to said standard and at the other end to said rotor for imparting angular movement to said mercury switch under conditions of variable temperature,

and electrical connections extending from said switch through said rotor to said electrically conductive plate members whereby said plate members constitute terminals for said switch.

5. A thermostatic electric circuit controller comprising a base of insulation material, a frame structure insulatingly supported with respect to said base, said frame structure comprising a pair of electrically conductive plate members, spacer members disposed between opposite ends of said plate members, a rotor journaled intermediate said plate members and comprising a disc of insulation material, a pair of conductive discs disposed on opposite sides of the aforesaid disc, a stub shaft carried by each of said conductive discs and projecting substantially normal thereto through journals in said plate members with said disc of insulation material interposed between the inner ends of said stub shafts, a bracket member carried by'one of said stub shafts, a mercury switch supported by said bracket member, elec trical connections extending from said mercury switch to the respective conductive discs, terminals electrically connected with said conductive plate members, and a thermo-sensitive element insulatingly supported at one end with respect to said base and connected at the other end with said rotor for imparting angular movement to said mercury switch under conditions of variable temperature.

6. A thermostatic electric circuit controller comprising a base of insulation material, a frame structure insulatingly supported with respect to said base, said frame structure comprising a pair of electrically conductive plate members, spacer members disposed between opposite ends of said plate members, a rotor journaled intermediate said plate members, and comprising a disc of insulation material, a pair of conductive discs disposed on opposite sides of the aforesaid disc, a stub shaft carried by each of said conductive discs and projecting substantially normal thereto through journals in said plate members with said disc of insulation material interposed between the inner ends of said stub shafts, a bracket member carried by one of said stub shafts, a mercury switch supported by said bracket member, elec- 8 trical connections extending from said mercury switch to the respective conductive discs, terminals electrically connected with said conductive plate members, a thermo-sensitive element supported at one end on said base, and means connecting the other end of said thermo-sensitive element with said rotor for imparting angular movement to said mercury switch under conditions of variable temperature.

'7. A thermostatic electric circuit controller comprising a base of insulation material, a frame structure insulatingly supported with respect to said base, said frame structure comprising a pair of electrically conductive plate members, spacer members disposed between opposite ends of said plate members, a rotor journaled intermediate said plate members and comprising a disc of insulation material, a pair of conductive discs disposed on opposite sides of the aforesaid disc, a stub shaft carried by each of said conductive discs and projecting substantially normal thereto through journals in said plate members with said disc of insulation material interposed between the inner ends of said stub shafts, a bracket member carried by one of said stub shafts, a mercury switch supported by said bracket member, electrical connections extending from said mercury switch to the respective conductive discs, terminals electrically connected with said conductive plate members, a thermo-sensitive element supported at one end on said base and free to flex at the other end thereof, a transverse pin carried by the free and of said thermo-sensitive element and projecting through a slot formed in said rotor for imparting angular movement to said mercury switch under conditions of variable temperature.

8. A thermostatic electric circuit controller comprising a base of insulation material, a frame structure insulatingly supported with respect to said base, said frame structure comprising a pair of electrically conductive plate members, spacer members disposed between opposite ends of said plate members, a rotor journaled intermediate said plate members and comprising a disc of insulation material and a pair of conductive discs disposed on opposite sides of the aforesaid disc, a stub shaft carried by each of said conductive discs and projecting substantially normal thereto through journals in said plate members with said disc of insulation material interposed between the inner ends of said stub shafts, a bracket member carried by one of said stub shafts, a mercury switch supported by said bracket member, electrical connections extending from said mercury switch to the respective conductive discs, terminals electrically connected with said conductive plate members, a thermo-sensitive element supported at one end on said base and free for angular displacement at the other end thereof, a transverse pin carried by the free end of said thermo-sensitive element and projecting through a slot formed in said rotor for imparting anguular movement to said mercury switch under conditions of variable temperature, and means for keying said conductive discs to said disc of insulation material for insuring simultaneous movement of all of the discs constituting said rotor.

RUSSELL ANDREW GRADEN.

No references cited. 

